著者

森 久史 伊藤 暁 辻村 太郎

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.70, no.8, pp.638-641, 2006 (Released:2006-08-22)

参考文献数

8

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This paper presented the results of application of super hydrophilicity TiO2 coating on Shinkansen vehicle. Also effect of metalic powder on hydrophilicity of TiO2 coatings was investigated. It was found that durability of protection from dirt adhesion was less than five months in real vehicle tests. The reason of degradation on protection was due to the contamination of metal powders produced by abrasive wear on the coating surface. Accordingly, it was considered that the degradation of hydrophilicity was attributed to the metal powder on the interface between TiO2 and water.

著者

小山 真司 川澄 健太郎

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.74, no.10, pp.656-661, 2010 (Released:2010-10-01)

参考文献数

9

被引用文献数

1 3

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The purpose of this study is the development of simultaneous processing of diffusion bonding and surface nitriding. Carbon steel was used as the base material. The surface was nitrided to a 20-μm-thick titanium foil. The sample was arranged in the order of carbon steel, titanium foil, and Al2O3 powder (diameter=1 μm) and placed in N2 gas in a furnace to undergo simultaneous diffusion bonding and surface nitriding. These processes were carried out at a processing temperature T of 1100~1250 K and processing pressure P of 0.5 MPa (processing time=4.8 ks). Because no defect was observed in the bonded interface, it was confirmed that a sufficiently suitable joint can be obtained under these processing conditions. The surface hardness was observed to increase with the increase in processing temperature; it reached approximately HV1600 at 1250 K. The surface of the titanium foil, which had been simultaneously processed at 1250 K, consisted of a single phase of TiN. The results of the ball-on-disc-type wear test revealed that the surface, which had been processed at 1250 K, was hardly worn by the TiN layer.

著者

古原 忠 安中 聡 牧 正志

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.72, no.12, pp.942-948, 2008 (Released:2008-12-01)

参考文献数

15

被引用文献数

2 2

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Effects of carbon addition on microstructure of Ti-V alloys formed at high temperatures were investigated.    By adding carbon to pure Ti and Ti-V binary alloys, precipitation of TiC occurs. With increase of vanadium content, β/(β+TiC) phase boundary shifts to the lower carbon side slightly. On the other hand (α+β)/(α+β+TiC) boundaries shifts largely with decreases in α fraction and peritectoid reaction temperature by addition of vanadium.    Addition of carbon to a Ti-15V-3Cr-3Sn-3Al alloy results in extensive suppression of recovery during hot deformation of β phase by carbon in solution. Also age hardening kinetics of Ti-15V-3Cr-3Sn-3Al after β solutionizing was accelerated by carbon addition.

著者

国谷 啓一 荒川 英夫 金井 恒行 千葉 秋雄

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.49, no.10, pp.906-912, 1985 (Released:2008-04-04)

参考文献数

10

被引用文献数

3 4

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We have developed a new material of copper-carbon fiber composite which possesses the properties of copper, i.e., the excellent electrical and thermal conductivities, and the property of carbon fiber, i.e., a small thermal expansion coefficient. These properties of the composite are adjustable within a certain range by changing the volume and/or arrangement of carbon fibers.The effects of volume and arrangement of fiber on the thermal conductivity, electrical conductivity and specific heat of the composite were studied. Results obtained are as follows:(1) The thermal and electrical conductivities of the composite became smaller as the volume of carbon fiber increased, and were influenced by the fiber arrangement.(2) The above results were predictable from a careful application of the “rule of mixtures” for composites.(3) The specific heat of the composite was dependent not on the fiber arrangement but on the fiber volume.(4) In the thermal fatigue tests, no degradation in the electrical conductivity of this composite was observed.

著者

村田 純教

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.80, no.11, pp.669-683, 2016 (Released:2016-10-25)

参考文献数

57

被引用文献数

3

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Lath Martensite is formed in low carbon steels and plays an important role in the mechanical properties of heat resistant steels containing about 0.1 mass%C. The lath martensite shows the hierarchic microstructure being composed of packet, block and lath. Martensitic transformation is the phase transformation accompanying orderly shear deformation without atomic diffusion. Relaxation of the strain energy caused by the deformation is the origin of the hierarchic microstructure but the formation mechanism of this microstructure has heretofore not been understood. In this paper, we survey first both the experimental results and phenomenological formation mechanism of the lath martensite reported so far and introduce a new mechanism (Two Types of Slip Deformation model: TTSD model), which is constructed by considering, independently, two kinds of slip deformations using the slip deformation model proposed by Khachaturyan. It is also introduced that TTSD model enables us to simulate the martensite phase formation by the phase-field method. Furthermore, it is found that TTSD model allow us to predict the features of lath martensite, such as the existence of sub-blocks and high dislocation density in lath. In particular, for the first time, the reason why laths in a block structure exist, can be clearly explained by TTSD model.

著者

塩原 融 中岡 晃一 和泉 輝郎 加藤 丈晴

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.80, no.7, pp.406-419, 2016 (Released:2016-06-25)

参考文献数

145

被引用文献数

9

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Since the discovery of the YBCO superconductor, many efforts have been made to develop useful superconductive wire and tape for many electrical power applications. Especially, the second generation coated conductors using REBaCuO (RE: rare earth element, Y, Gd, Sm, Nd, Eu etc) compounds have high expectations because of its high critical current density at the liquid nitrogen temperature and under self fields as well as high magnetic fields. Recently, several processes have been successfully developed to introduce effective magnetic flux pinning centers into the REBCO layer in order to enhance the in-field critical current densities. This paper reviews the present status of the research and development about the improvement of critical currents in considerations of nano-scale microstructure.

著者

譚 毅 篠田 哲守 三島 良直 鈴木 朝夫

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.57, no.3, pp.356-361, 1993 (Released:2008-04-04)

参考文献数

21

被引用文献数

1 2

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With boron-doped NiAl alloys, the solubility of boron, the composition and structure of the precipitated boride and the change in fracture mode due to boron addition have been studied. The solubility of boron is very small on the Ni-rich side of the alloys with a slight increase in its magnitude with deviation from the stoichiometric composition of the alloys, while the solubility of boron on the Al-rich side can be neglected. The structure of the precipitated boride on the Ni-rich side of the NiAl(45 at%Al) alloy is a Cr23C6 type compound, where composition is Ni60Al10B30 and the lattice parameter of which is 1.0542 nm.The fracture mode for the alloys changes from the intergranular to the transgranular type of fracture as an increase in boron concentration for both sides of Ni- and Al-rich compositions. However, the critical concentration of boron to the mode change in fracture mode is 0.003 mass% on the Ni-rich side, whereas it is 0.02 mass% on the Al-rich side.

著者

松本 仁

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.66, no.12, pp.1350-1355, 2002 (Released:2008-04-24)

参考文献数

27

被引用文献数

1 7

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The transformation behavior of near equiatomic NiTi alloys were precisely measured by a four-probe potentiometric method in order to investigate the effects of the repetition of the transformation with thermal cycling. Complete and incomplete thermal cycles induce an anomalous increase in electrical resistivity which is attributed to formation of the R-phase. The incomplete thermal cycle is effective in the formation of the R-phase in comparison with the complete thermal cycle. The behavior of the transformation to the R-phase with thermal cycles depends on the composition and it is more difficult to induce and stabilize the R-phase by thermal cycling in NiTi with higher Ms. The characteristics on the effects of the thermal cycles are the shift of the Ms to the low-temperature side and the stabilization of the R-phase, which are taken to be attributable to the accumulation of transformation-induced defects. The precise measurement of the electrical resistivity proved helpful in order to detect the trace of the R-phase and characterize the effects of the thermal cycles.

著者

千野 靖正 黄新 胜 鈴木 一孝

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.81, no.2, pp.49-54, 2017-02-01 (Released:2017-01-25)

参考文献数

41

被引用文献数

18

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Magnesium (Mg) alloys are suitable materials for weight reduction in vehicles because of their low densities and high specific strengths. However, rolled Mg alloy sheets generally exhibit a poor formability at room temperature and thus their applications are restricted. This poor formability is originated from basal slip dominated deformation as well as strong basal texture. It is known that the formability can be improved by suppression of basal texture formation. Thus, large efforts have been devoted to texture control for the purpose of enhancing the room temperature formability. In this paper, recent researches for texture control of rolled Mg alloy sheets are reviewed.0

著者

林 重成 高島 大 河内 礼文 西山 佳孝

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.81, no.9, pp.417-426, 2017-09-01 (Released:2017-08-25)

参考文献数

11

被引用文献数

1

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High-temperature oxidation behavior of Fe-Ni-Cr alloys with different Ni contents in air and steam at 700°C was investigated. Oxidation mass gain in steam was higher than that in air. In both atmospheres oxidation mass gain tended to decrease with increasing Ni content. However, the Ni concentration dependence of oxidation mass gain in air was complex, i.e., oxidation mass gain increased with increase in Ni content up to 35% then decreased with higher Ni content. But oxidation mass gain of binary Ni-20Cr significantly increased. Such a complex oxidation behavior was not observed when alloys were oxidized in steam. The internal oxidation zone was locally formed in air, and a Cr2O3 scale was found to develop on the areas without internal oxidation. The size of area, where an internal oxidation zone was developed, changed depending on Ni content. In steam, most of the surface area of alloys was covered by an internal oxidation zone. Cr content, 20%, was considered to be insufficient but close to the critical Cr content for exclusive Cr2O3 scale formation in air. The critical Cr content for exclusive Cr2O3 scale formation was found to depend on alloy Ni content due to lower oxygen permeability in alloys with higher Ni content and the cross-term effect for Cr outward diffusion.

著者

大村 友希 河合 秀将 村山 憲弘 芝田 隼次

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.74, no.10, pp.677-681, 2010 (Released:2010-10-01)

参考文献数

16

被引用文献数

1 5

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Analysis of the chemical composition of spent cylindrical Li-ion batteries for PC, and investigation of the separation of each metal (Li, Co, Ni, Cu) from the Li-ion batteries were carried out by burning under a vacuum, crushing and screening, in order to recover rare metals from the Li-ion batteries.    The cylindrical Li-ion batteries have the structure that the multi-layered electrodes with four−layered foils composed of anode, cathode and two separators are enrolled cylindrically around the core steel bar. Seven kinds of metal such as Li, Co, Ni, Fe, Mn, Al and Cu mainly exist in the Li-ion battery. The whole mass of Li-ion battery used in this study is 39.7 g. The mass of Li, Co, Ni and Cu is 1.38 g, 10.3 g, 0.236 g and 4.62 g, respectively, in one piece of Li-ion battery, while other elements (graphite) are 23.16 g. Three size fractions of 150-125, 125-106 and 106-90 μm obtained by crushing and screening after burning under a vacuum and removing stainless case show almost similar compositions. On the other hand, the size fraction of +425 μm contains a lot of foil-like materials. The separation of Al and Cu with a larger particle size from the crushed product of a burned Li-ion battery is accomplished by using a 425 μm sieve. It is important to separate the foil-like elements such as Al, Cu and Fe from the crushed products of electrode materials by using a sieve with a larger mesh size, for example 5-10 mm.

著者

増田 高大 瀧沢 陽一 湯本 学 小田切 吉治 堀田 善治

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.80, no.9, pp.593-601, 2016 (Released:2016-08-25)

参考文献数

40

被引用文献数

2 7

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In this study, the method of high-pressure sliding (HPS) was applied for grain refinement of an A2024 alloy. Sheet samples with 10-15 mm width and 100 mm length with 1 mm thickness were processed by HPS under pressures of 2-3 GPa. Microstructural observations revealed that the grain size was refined to ~200 nm. Tensile tests showed that the ultimate tensile strength reached 886 MPa with a total elongation of 7.1% and the anisotropy of samples was less developed in the HPS-processed samples. Extra strengthening was attained by aging at 423 K after HPS processing, leading to an ultimate tensile strength of 967 MPa at the peak aged condition. Superplastic elongation of more than 400% appeared when the A2024 alloy processed by HPS for 20 mm was deformed in tension at a testing temperature of 623 K with an initial strain rate of 1.0×10−3 s−1.

著者

平野 賢一 大内 権一郎

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.32, no.7, pp.613-618, 1968 (Released:2008-04-04)

参考文献数

28

被引用文献数

3 15

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Reaction-diffusion in the Ti-Ni system was investigated in the temperature range between 500° and 900°C, using diffusion couples of pure Ti and pure Ni.Above the eutectoid temperature of the β-Ti solid solution, the greater part of the diffusion zone consisted of β-Ti, while the Ni solid solution scarcely grew in it at the experimental temperatures.All of the three intermediate phases, TiNi3, TiNi, Ti2Ni, existing in the equilibrium phase diagram were observed in the diffusion zone at all the experimental temperatures. The apparent activation energies for the growth of TiNi3, TiNi, Ti2Ni phases are 16.1, 27.2 and 11.9 kcal/mol, respectively. It appears that such low activation energies are attributed to the excess vacancies in the intermediate phases of nonstoichiometric compositions.The composition range of the TiNi phase was determined from the concentration-penetration curves of the diffusion couples, and compared with the results of other workers. The composition range tends to decrease as temperature decreases, and at the Ni-rich side it is in good agreement with that obtained by Hume-Rothery et al. and Parr et al., but at the Ti-rich side it is displaced to the Ti-richer side.

著者

増本 健 奈賀 正明 今井 勇之進

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.34, no.2, pp.195-201, 1970 (Released:2008-04-04)

参考文献数

21

被引用文献数

1 6

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Studies on the equilibrium between austenitic iron and nitrogen under various conditions of the maximum pressure of 920 kg/cm2 and the temperature range of 950°∼1300°C were carried out using a high temperature-high pressure equipment. It was shown that the concentration of nitrogen in austenite deviates from Sieverts’ law with increasing pressure. The cause for such discrepancy was considered thermodynamically and statistically. That is, the experimental result can reasonably be explained from the geometrical consideration that the chemical potential of a nitrogen atom in austenite with a high nitrogen content, departs remarkably from the value for the ideal random interstitial solid solution, since each interstitial atom added excludes other interstitial atoms from the seven adjacent sites. Thus, the activity of nitrogen in austenitic iron can be expressed by the following equations:(This article is not displayable. Please see full text pdf.)

著者

平山 俊成 小切間 正彦

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.34, no.5, pp.507-510, 1970 (Released:2008-04-04)

参考文献数

21

被引用文献数

17 74

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In order to investigate the martensitic transformation in Fe-Cr-Ni stainless steel, the Ni equivalent has been introduced thermodynamically as a universal quantity which indicates stability of austenite with regard to chemical composition. The relation between the Ni equivalent and the amount of strain-induced martensite or athermal martensite has been studied by means of saturation flux density measurement. Furthermore, the mechanism of the formation of strain-induced martensite has been considered thermodynamically.The results obtained are summarized as follows:(1) The Ni equivalent, (Ni), in Fe-Cr-Ni stainless steel is expressed by\phantom(1)(Ni)=Ni+0.65Cr+0.98Mo+1.05Mn+0.35Si+12.6C\ oindentwhere Ni, Cr, etc. represent weight % of these elements in the stainless steel considered.(2) The relation between the Ni equivalent and the amount of strain-induced or athermal martensite has been obtained.(3) About 75% cold rolling of Fe-Cr-Ni stainless steel has the same effect on martensitic transformation as decreasing the Ni content by 3∼5%. In this case, the difference in the free energy at room temperature between the ferrite phase and the austenite phase increases by about 113∼188 cal/mol.(4) The deduced value of the work done by transformation strain induced by the applied stress due to cold rolling is about 120∼126 cal/mol or about 192 cal/mol by compressive or tensile stress, respectively. These values agree very well with the above mentioned change of the free energy difference calculated from the variation in Ni equivalent. Therefore, under applied stress, the stored free energy required for martensitic transformation can be lowered by this work value, 120∼192 cal/mol.

著者

中村 崇 植田 安昭 Toguri James M.

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.50, no.5, pp.456-461, 1986 (Released:2008-04-04)

参考文献数

33

被引用文献数

5 35

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A new scale of the theoretical optical basicity was established by means of the concept of the average electron density (D) expressecl in eq. (1).(This article is not displayable. Please see full text pdf.) \ oindentThe value of α in an oxide system was defined unity, and the values of α in alkaline earth fluoride and chloride systems were determined by measurments of Pbs-p spectra of CaF2 and CaCl2 using photoacoustic spectroscopy.The basicity moderating parameter values were found to have a linear relation with the values of the average electron density, as shown in eq. (2).(This article is not displayable. Please see full text pdf.) The theroretical optical basicity values of transition metal oxides were able to be calculated in the new scale, for example, ΛFeO=0.94, ΛFe2O3=0.72 and ΛTiO2=0.65. It was possible to explain the sulfide capacity values in the systems containing iron oxides using these optical basicity values. The theoretical optical basicity values of alkaline earth fluoride and chloride were also obtained in this study. The values of the optical basicity showed a good correlation to logarithmic values of the phosphate capacity at a constant temperature in the systems consisting of oxide and fluoride compounds. It is suggested that the theoretical optical basicity developed in this study was a resonable scale for a wide range basicity in slags and fluxes.

著者

渋江 和久 熊谷 正樹 金 睦淳

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.56, no.12, pp.1457-1462, 1992 (Released:2008-04-04)

参考文献数

10

被引用文献数

3 10

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The oxidation property of a Ti-33.5 mass%Al-2.5 mass%Mn intermetallic compound prepared by a reactive-sintering process was studied at 1223 K in air in comparison with that by a melt process. The reactive-sintered alloy had been found to have superior oxidation resistance to the melted one. The oxidation scale of the former was suggested to be adhesive, for example, owing to the presence of fine alumina particulates and/or pores which contribute to pegs. The fine alumina particulates were developed by breaking up of the oxide layer along prior particle boundaries during the reactive-sintering process.

著者

山口 正剛

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.72, no.9, pp.657-666, 2008 (Released:2008-09-01)

参考文献数

20

被引用文献数

10 37

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The microscopic mechanism of the grain boundary embrittlement in metals by solute segregation has been not well understood for many years. From first-principles calculations, we show here that the calculated cohesive energy (2γint) of bcc iron Σ3(111) symmetrical tilt grain boundary is reduced by the segregation of sulfur (S) or phosphorous (P), while it is increased by the segregation of boron (B) or carbon (C). The rate of the decrease/increase in the 2γint was excellently proportional to the experimental ductile-to-brittle transition temparature (DBTT) shift with increasing segregation; this demonstrates that the grain boundary embrittlement is governed by the change in the 2γint.

著者

桐野 文良 北田 正弘

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.79, no.2, pp.57-63, 2015

被引用文献数

3

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&nbsp;&nbsp;The microstructures of a corrosion layer formed on the surface of two Japanese oldest coins, <i>Wadoukaichin</i> (surface color: dark brown and green) were studied. Compositions of these coins are that main element is Cu and Sn and traces are Pb, Fe and As. X-ray diffraction patterns show that copper di-hydroxide (Cu(OH)₂ 2H₂O), Cu_1.81S and Cu₂O are detected on the surface corrosion layer of dark brown sample, and Cu₂(CO₃)(OH)₂ (malachite), Cu₃(CO₃)₂(OH)₂ (azurite) and Cu₂O are detected on the surface corrosion layer of green sample. Optical microscope images show that the surface corrosion layer of dark brown sample is porous, and blue and green grains on the brown layer are existed on that of green sample. From spectrographs of these grains, the peak wavelength of green grains is matched to that of malachite, but this of blue grains is shifted to long wavelength side of about 40 nm at azurite on an influence of trace contaminations. The corrosion layer has two layers, surface layer is plate-like texture, and under layer is aggregation microstructure from TEM observation. The crystal structure of these two layers is matched to azurite from the electron beam diffraction patterns.<br>

著者

北田 正弘 高妻 洋成 肥塚 隆保 建石 徹

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.79, no.2, pp.71-75, 2015

被引用文献数

6

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&nbsp;&nbsp;The mural of the <i>Takamatsuzuka</i> tumulus in Asuka, Nara prefecture, was painted in the 7-8th centuries. Red, green, blue, yellow, and black pigments are used in the mural. The microstructure of one of them, the red pigment, was described in the previous paper. In this study, the black pigment observed within the red pigment area has been investigated. An optical microscope, a scanning electron microscope, and a transmission electron microscope are utilized to examine the microstructure. Among the black particles, two different Fe compounds are observed. One is magnetite (Fe₃O₄) comprising small amounts of Ti, Al, and Mg, and the other is ilmenite (FeTiO₃) containing a small amount of Mg. In addition to the above compounds, an oxide particle containing Zr is also observed.<br>